Tamper proof sprinkler head



Aug. 22, 1950 A. c. ROWLEY 2,519,704

TAMPER PROOF SPRINKLER HEAD Filed Nov. 28, 1949 i A l; v

. rk (PIP/0}? ear) 5 Patented Aug. 22 1950 UNITED STATES PATENT 7 OFFICE TAMPER PROOF SPRINKLER HEAD Arthur C. Rowiey, Drexel Hill, Pa, assignor to Globe Automatic Sprinkler :Company, Philadelphia, Pa, a corporation of Pennsylvania Application November 28, 1949, "Serial No. 128,839

.1 This invention relates to automatic sprinkler systems and more particularly to a novel form of sprinkler head.

A principal object of the invention is to provide a substantially tamper-proof sprinkler head. Another object of the invention is to provide a sprinkler head wherein the spreader element forming a conventional part of such heads is divorced from the closure retaining function as hereinafter more specifically described.

Another object of the invention is to provide a tamper-proof sprinkler head which employs a hardened cement as a means for anchoring the operative elanents in place in the frame of the sprinkler head and preventing access. to said elements for unauthorized tampering.

The invention resides further in certain structural details hereinafter described and illustrated in the attached drawings wherein;

Fig. 1 is a side elevaitonal View of a sprinkler head made in accordance with the invention;

Fig. 2 is an enlargedfragmentary sectional view on the line 2-2. Fig. 1;

Fig. 3 is a still further enlarged fragmentary sectional view showingthe details of the antitampering means;

Fig. 4 is a fragmentary sectional view showing a prior conventional device for maintaining the temperature responsive elements in the normal operative position;

Fig. 5 is a fragmentary front elevationalview of amodified form of sprinkler head made in accordance with the present invention;

Fig; .6 is a side elevational View of the sprinkler head shown in Fig. 5; and,

Fig. 7 is an enlarged sectional view on the line 1-1, Fig. 5.

With reference to the drawings, the sprinkler head illustrated in Fig. -1 comprises the conventional frame designated generally by the reference numeral 1, said head having a nozzle 2 at one end, and arms 3"which extend from the sides of the nozzle to a point beyond the discharge end of the latter and which come together at their outer ends in a hollow internally threaded juncture 4, the threaded bore being in alignment with the axis of the nozzle 2 The sprinkler head includes also a closure disc 5. which normally seats at the discharge end of the nozzle 2, and a thermally responsive release device or member Gfor said closure which is confined'under pressure between the closure and a retaining screw 1 adjustably supported inthethreadedhore of the juncture 4.

Thearrangement of elements described above will be better understood by reference to Fig. 2

2 wherein the threaded bore of the juncture :4 isindicated by the reference numeral 8. It will be apparent that the screw 1 exerts pressure on the closure element 5 by way of the thermally responsive release member 5 to maintain the closure disc 5 in the normal operative position. In the present instance, a gasket 9 is provided between the end of the nozzle 2 and the closure disc 5, said gasket having a central concave portion H which extends into the end of the nozzle bore and forms a housing for a spring H! which is held under compression between the gasket and the inner face of the disc 5. It will be noted also that the screw 1 bears against an element l3 which is recessed at It for reception of the end of the thermally responsive member ii, the element 1 3 also having a central boss l 5 which projects into a recess It in the confronting end of the screw 1. The thermally responsive release device 6 which operates under longitudinal compression to hold the closure disc in place may be of conventional form.

In sprinkler heads of the character described, it is important in order to insure against malfunction under, operating conditions that means he provided for preventing tampering which might alter the original setting of the component elements. Heretofore, it has been proposed to'prevent tampering by anchoring the adjustable retaining member by positive means to the frame, as, for example, by the device illustrated in Fig. 4 wherein the retaining screw I? is locked in the frame by means of a riveted pin it. Devices of this character have not proved entirely efiective due, in part, to the fact that such pins, necessarily small, can be sheared by forcible turning of the screw llthrough the medium of a deflector element [9 which conventionally is attached to the outer end of the screw.

With reference again to Figs. 1 and .2 of the drawings, it will be noted that the sprinkler head I is provided with the conventional spreader 2| supported on the frame in alignment with the nozzle 2 and at the opposite end of the frame from i said nozzle. In accordance with the present invention; the spreader 2! is divorced from the closure retaining screw l and is carried on a separate screw stem 22 which, in assembly, is threaded into the outer end of the bore '3. Between the inner end of the threaded stem 22 and the proximate end of the screw 1 is a mass 23 of hardened cement, this cement being compacted in the inner space between the screws by action of the stem 22 upon the mass while still in the plastic or fluid condition. As a result of this compression of the cementitious material while in the fluid state, portions thereof are forced into the interstices of the screw threads as indicated at 24 in Fig. 3 so that the cement, when set and hard, acts not only to lock the screws I and 22 in place but also forms an abutment in the bore for the inner or socketed end of the screw 1 which positively prevents backing off of this screw from its normal adjusted pressure contact with the thermally responsive release member 8. As set forth above, the cementitious material acts to lock the threaded stem 22 in the bore, but assuming that this screw were displaced by unauthorized parties from the outer end of the bore, the mass of the hardened cement 23 would still bar admission to the socketed end of the screw 1 of a turning tool. While the composition of the cementitious material may vary widely, a cement composed of finely divided litharge and glycerine, well known in the plumbing trade, has been found well suited to the purpose, such cement, when properly compounded, setting to a hard stone-like state.

Attention is directed to the manner in which the spreader element 2|, which is conventionally made in the form of a separate stamping from sheet metal is connected to the threaded stem 22. The inner peripheral portion 25 of the spreader is confined within a circumferential slot 26 in the outer head end of the stem 22, said slot being formed by upsetting the outer end portion of the stem against the outer face of the spreader in obvious manner. Conventionally, the said outer end portion of the stem is upset first to the form indicated in broken lines in Fig. 2 so as to provide a shoulder '2'! that may be gripped by pliers or other tool devices for turning the threaded stem forcibly into the bore 8 against the mass of cement23. This is in accordance with the conventional practice followed in the instances where the spreader 2| is directly connected to the closure retaining screw as in the construction illustrated in Fig. 4. After the stem 22 has been threaded into the bore 8 and into compression relation with the mass of the cementitious material 23, the outer end of the stem is peened over as indicated in full lines at 28 so as to eliminate the shoulder 21. Normally the spreader Zl' will be firmly anchored in the slot 26 but will turn in said slot if the applied'torque is of suflicient magnitude before releasing the threads of the stem from the cement lock afforded as described above.

It will be apparent, therefore, that the device is substantially tamper-proof in that removal of the threaded stem of the spreader 2| by unauthorized parties is virtually impossible and further in that such removal would still fail to alford access to the retaining screw 7 by reason of the hardened cement mass 23 which, as previously set forth, functions not only to positively lock the retaining screw I in the advanced operative position but also to bar admission to the socketed end of the screw of a turning tool.

The device is applicable in principle to other forms of sprinkler head such, for example, as that illustrated in Figs. 5, 6 and '7. In this case the deflector 29, which corresponds to the element 2! of the previously described embodiment, is of a type adapted for use with sprinklers located in proximity to side walls. The deflector member is mounted upon a shoulder 3| of the frame 32, said deflector having a cylindrical bore 33 which closely embraces the reduced upper end 34 of the said frame. The deflector is locked in position by a screw 35 which is threaded into the outer end of the bore 36 of the frame and which has a head portion 31 which extends outwardly over the outer surface 38 of the deflector. Before the outer end portion of the screw 35 is riveted over the outer face of the spreader, it is available for engagement by a suitable turning tool for forcibly turning the screw inwardly against the mass of cement material 39 which is located in the bore at the end of the closure retaining screw 4!. After the screw 35 has been turned in tightly against the cement mass, the outer terminal end may be upset to form the smoothly curved rivet end 42 as shown in Fig. 7 It will be noted by reference to Figs. 5 and 6 that in this case the side flang portions 43 of the deflector 29 are notched for interlocking engagement with the arms M of the frame so that when assembled the deflector is locked against rotational movement about the axis of the bore 36. The riveted head of the screw 35 functions, therefore, merely to secure the deflector 29 against axial displacement thereof on the frame.

I claim:

1. In a sprinkler head, a frame having a nozzle at one end, a closure for said nozzle, a closureretaining element adjustably mounted in the other end of the frame, a thermally responsive release member confined under pressure between the closure and said retaining element, and means including a mass of hardened cement for maintaining the said element in operative position.

2. A sprinkler head according to claim 1 wherein the retaining element consists of a screw mounted in a threaded bore in the frame, the said cement occupying a position in the bore behind the screw to lock the screwin position and to bar admission to the screw of a turning tool.

3. A sprinkler head according to claim 2 wherein the outer end of the bore is plugged by a threaded element which covers the body of cement, said cement extending into the clearance spaces between the threads of the bore and the threads both of the retaining screw and of the said threaded plug element and thereby cementing the screw and plug in the bore.

4. A sprinkler head according to claim 3 wherein a spreader element is carried by the plug element.

5. A sprinkler head according to claim 4 wherein the spreader is annular in form and is mounted with its inner peripheral portion confined within a circumferential slot in the head of the plug element, said spreader being rotatable in the slot under a torque of lesser magnitude frame opposite the nozzle.

ARTHUR C. ROWLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,801,569 Phillips Apr. 21, 1931 2,291,813 Knight Aug. 4, 1942 

